1. Field of the Invention
The present invention relates to a cosmetic formulation comprising a cosmetically acceptable medium and at least one silver-colored pigment, the silver-colored pigment comprising a nonmetallic platelet-shaped substrate and at least one ilmenite-containing coating.
2. Description of Related Art
The use of silver-colored effect pigments in cosmetic formulations is subject to strict regulatory impositions with regard to the size and nature of the pigment employed. For example, according to FDA Code of Federal Regulation Title 21, Volume 1, 73.1645 in the USA, aluminum effect pigments which do not pass fully through a screen with a mesh size of 200 mesh may not be used in the color cosmetics sector. According to this ordinance, furthermore, the use of aluminum effect pigments is not permitted in the area of the lips and of the mouth in cosmetic formulations. Consequently, for example, global marketing approaches for lipsticks which contain aluminum effect pigments are not possible. From the standpoint of market strategy, such restriction is undesirable.
If it is desired to have the metallic effect and the visual impression of an aluminum effect pigment in a cosmetic formulation, then it is not possible simply to replace the aluminum effect pigment by a silver-colored pearlescent pigment. In terms of their optical properties, metallic effect pigments and pearlescent pigments differ fundamentally from one another.
Metallic effect pigments have a hard metallic specular gloss, whereas pearlescent pigments exhibit a soft velvety gloss which appears to come from deep down.
Commercial silver-colored pearlescent pigments generally do not possess the neutral silver hue that is characteristic of aluminum effect pigments. Nor can the opacity of opaque metallic effect pigments be achieved by pearlescent pigments, which are typically transparent. There is a need, therefore, for pigments for cosmetic formulations that in terms of the optical properties such as, for example, silver color with metallic appearance, opacity, metallic gloss or light/dark flop, come close to metallic effect pigments, and yet contain no metal, such as aluminum, for example. Furthermore, in addition to the criteria already specified, the intention is to provide heavy-metal-free and more light-stable alternatives to silver-colored pigments consisting of or comprising bismuth oxychloride.
The problem on which the present invention was based was that of providing a cosmetic formulation which comprises water-stable, high-gloss, silver-colored pigments. In terms of their visual impression, the silver-colored pigments are to have the properties characteristic of metallic effect pigments. In terms of their appearance, the silver-colored pigments are to differ not at all, or only insubstantially, from commercial aluminum effect pigments. At the same time, the silver-colored pigments are to be distinguished by a high stability, especially with respect to acids, bases, acidic or alkaline cosmetic ingredients, and aqueous or protically/aprotically polar media, and also by their temperature stability. Furthermore, the silver-colored pigments, which are to be suitable for use in the cosmetic formulation, are to be free-flowing and have no propensity toward dust explosion.